Community involvement has played a central role in the tight against HIV/AIDS since the beginning of the epidemic. Volunteers and activists led the first prevention and care efforts in their communities. In the process of mobilizing, they became educated about HIV/AIDS, developed a sense of community and a positive self-identity, and mobilized their social support to cope with the epidemic. Thus, individuals' community involvement has critical public health implications. First, through their involvement in HIV/AIDS-related organizations, individuals develop a positive sense of themselves and become educated about HIV/AIDS. Second, via this involvement individuals affect change in their communities. Yet, research and prevention programs have overlooked community involvement as a mechanism to reduce HIV/AIDS sexual risk behavior among minority gay/bisexual men. The overall goal of the proposed research program is to investigate the protective effects of community involvement in HIV/AIDS-related groups and organizations for HIV/AIDS sexual risk behavior among Latino gay/bisexual men. The specific aims include: 1. Examine the protective effects of community involvement in HIV/AIDS for Latino gay/bisexual men's sexual risk behavior. We will test the moderating effects of community involvement on the association between three socio-structural risk factors (i.e., poverty, racism, and homophobia) and sexual risk behavior. 2. Refine and test a model of the mediating factors (i.e., peer norms, self-efficacy, positive self-identity, and alienation) of the association between community involvement and HIV/AIDS sexual risk behavior. 3. Examine the socio-cultural barriers to and facilitators of Latino gay/bisexual men's community involvement in HIV/AIDS. This research will be conducted in three phases in Chicago and San Francisco. 1. Using life history methods we will define the concept of community involvement in HIV/AIDS and refine our theoretical models. 2. We will develop and test measures. 3. We will test the protective effects community involvement (Aim I), the model of the mediating factors (Aim 2), and the barriers/facilitators for community involvement (Aim 3) in a cross-sectional survey of Latino gay/bisexual men (N=600).